<!DOCTYPE HTML>
<html><body>
<p>Turn on &quot;Start Debugging JavaScript&quot;, open the JavaScript
  console, refresh, and then type &quot;2+3&quot; in the JavaScript console.
  If it shows an Error with an closed triangle, open the triangle to
  see the error.
<script>
  (function(){
    "use strict";
    debugger;
  })();
</script></body></html>
